§ 53.73 METERED BILLABLE FLOW RATE DETERMINATION.
   (A)   Generally.
      (1)   Each user shall pay operation, maintenance and replacement costs in proportion to the user’s proportionate contribution of wastewater flows and loadings to the treatment plant, with the minimum rate for loadings of BOD and TSS being the rate established for concentrations of 200 mg/1 and BOD and 250 mg/l TSS (such as, normal domestic strength wastewater).
      (2)   Those "industrial users" discharging segregated "normal domestic strength wastewater" only, can classified as "commercial users" for the purpose of rate determination.
   (B)   User charges for normal domestic strength users.
      (1)   Calculating billable flows and loadings. The charges assessed residential users and those of other classes connected to the city’s water utility and discharging "normal domestic strength wastewater" shall be established proportionately according to billable wastewater volume. Billable wastewater volume shall be calculated as follows:
         (a)   Measurement of wastewater volume for residential users.
            1.   Measurement of wastewater volume for residential users connected to the city’s water utility. Except as provided for herein, billable wastewater volume for residential users shall be calculated on the basis of metered water usage.
            2.   Measurement of wastewater volume for residential users not connected to the city’s water utility.  
               a.   The charges assessed residential user and those users of other classes discharging "normal domestic strength wastewater" who are not connected to the city’s water utility shall be estimated.
               b.   Residential users may appeal the number of ERU’s assigned to a particular connection by installing and maintaining, at their own expense, water meters of a type approved by the city. The meters shall be equipped with remote registering recorders located at an accessible site on the owner’s property.
The city reserves the right to require residential users to install water meters for the purpose of determining billable wastewater volume.
         (b)   Measurement of wastewater volume for nonresidential users.
            1.   The charges assessed nonresidential users discharging "normal domestic strength wastewater" shall be established proportionately according to billable wastewater volume. Billable wastewater volume shall be calculated as follows: the billable wastewater volume of nonresidential users may be determined in the same manner as for residential users connected to the city’s water utility. Except that if the city determines that there are significant seasonal variations in the metered water usage of nonresidential users resulting in a proportionate increase (or decrease) in wastewater volume, then billable wastewater volume shall be calculated on the basis of quarterly metered water usage recorded throughout the year, calculated on the basis of wastewater flow meters.
            2.   The city may, at its discretion, require nonresidential users to install a water meter, or such additional water meters or wastewater flow meters as may be necessary to determine billable wastewater volume.
         (c)   Determination of loadings for normal domestic strength users. The billable amounts of BOD and TSS will be calculated from the volume of metered water usage, as determined above, where the billable quantities will be those attributable to wastewater at a concentration of 200 mg/l BOD and 250 mg/1 TSS (such as, "Normal Domestic Strength Wastewater").
      (2)   Determination of user charges for normal domestic strength users. 
         (a)   User charges for normal domestic strength users.
 
Un =
Comr
 
Tbwv
 
            Where:   Un =   Unit cost for operation, maintenance and replacement to treat normal domestic strength, in $/Kgal.
                  Comr =   (Total annual OM&R costs) - (charges collected to treat concentrations greater than normal domestic strength; in accordance with § 52.74(E).
                  Tbwv =   Total annual billable wastewater volume in Kgal.
         (b)   Calculation of user charge for normal domestic strength wastewater.
               Un = Un X bwv
            Where:   Uc =   User charge
                  Un =   Unit cost for operation, maintenance and replacement to treat normal domestic strength in $/Kgal.
                  bwv =   Billable wastewater volume of a particular user in Kgal.
         (c)   Calculation of administrative charge for normal domestic strength wastewater.
               Ad = Cad ÷ #eu
            Where:   Ad =   Administrative Charge per user.
                  Cad =   Total budget for administrating and treating I/I.
                  #eu =   Number of equivalent users.
   (C)   The sewer service charges established in this subchapter shall not prevent the assessment of additional charges to users who discharge wastes with concentrations greater than normal domestic strength or wastes of unusual character or contractual agreements with such users, as long as the following conditions are met:
      (1)   The user pays operation, maintenance and replacement costs proportion to the user’s proportionate contribution of wastewater flows and loadings to the treatment plant, and no user is charged at a rate less than that of “normal domestic strength wastewater.”
      (2)   (a)   The measurements of such wastes are conducted according to the latest edition of Standard Methods for the Examination of Water and Wastewater, in a manner acceptable to the city as provided for in this subchapter.
         (b)   A study of unit costs of collection and treatment processes attributable to flow, BOD, TSS and other significant loading shall be developed for determining the proportionate allocation of costs to flows and loadings for user discharging wastes of greater than normal domestic strength or wastes of unusual character.
(Ord. 203, passed 9-1-1987; Am. Ord. 2011-06-07D, passed 6-7-2011)